As a representative for each signed rooted tree \(\mathcal {T}\) , one may take the local model \(L_\mathcal {T}\subset T^*{\mathbb {R}}^n\)  detailed in Section , where
\(n=|n(\mathcal {T})|\)  is one less than the number of vertices in the tree.
The model \(L_\mathcal {T}\subset T^*{\mathbb {R}}^n\)  is given as the positive conormal to an explicit front \(H_\mathcal {T}\subset {\mathbb {R}}^n\)  defined by elementary equations. Our exposition in Section  is self-contained and the reader need not be familiar with [1]} or [2]}. In particular, we emphasize the inductive nature of the constructions, and reformulate signs to match inductive arguments to come.
